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Topic Review (Newest First)

04-05-2013 12:36 AM

Gold Finger

You can't adsorb happiness with activated carbon.

Or detect it with a test strip.

04-05-2013 12:35 AM

Gold Finger

Fun! I forgot to subscribe to my own thread and look at what I found! I just have to get in on this debate we don't want to have, so, realizing now the science does not know the mechanism, here's my two cents worth: There's no point in our theorizing beyond satisfying our own nagging inner voices since we are not the ones who are going to discover the truth as to the mechanism, but I for one am most satisfied by the antibody analogy (I too have nagging voices which demand answers where there are none). Healthy things fight off parasites one way or another. Also, yes Hoppy, it is magick until we understand the mechanism at which point it will become science. Good enough for me. I am tempted to enter into discussing the alleopathy theory but easily grow tired of trying to reason out maybes. A brief statement is all I can usually muster, so here's one just for laughs: maybe healthy plants give off positive electromagnetic happy vibes (auras) which make the grumpy algae feel like they cant hang. I'm actually not joking. HaH!

I don't think the existence of allelopathy in aquatic plants is a hypothesis. I believe adequate research has been done to prove it's existence. The question is, does it play a role in the plant/algae competition in a planted tank. My hypothesis is yes, but to such a small degree to be insignificant for our purposes. This debate seems to be of little value as far as the goal of keeping healthy algae free plants in an aquarium. The fact of the matter is that it's done everyday. If allelopathy was the primary reason for algae free tanks we would have problems after changing water, using activated carbon, keeping multiple varieties of plants together and even keeping certain invertebrates as allelopathy can effect lower life forms as well. Algae scrubbers would fail as a result of algacidic compounds released by plants. This is not the case.

The debate always seems to start over the hypothesis of competition of plants versus algae for nutrients and light. Since nutrients and light are abundant in a healthy planted tank it cannot be a competition. Both algae and plants are provided with excess of each. So this simplistic view doesn't hold water either. That's the primary reason I began searching for other causes.

I prefer to follow Occum's razor when dealing with problems. It states that among competing hypotheses, the one that makes the fewest assumptions should be selected. In 20th century language “KISS”, keep it simple stupid.

Using that logic let's visit the competition hypothesis. As I said nutrients and lighting are in abundance so algae and plants cannot be in competition for those nutrients. The obvious answer must be the form of nutrients we use. It's a fact that those nutrients are primarily inorganic compounds otherwise activated carbon would strip most of them away. When do we see algae blooms in a healthy planted aquarium? Disturbing the substrate, failure to remove decaying organics, too much light in a sparsely planted tank and over feeding all seem to be a common theme.

So it's my hypothesis that competition does exist but rather a competition for organic nutrients The problem arises when the competition hypothesis is explained. When we increase the organics we see algae blooms. The inorganics we use as nutrients must not be readily utilized by algaes we see. So the confusion comes when we don't preface the competition hypothesis by saying the nutrients we add are inorganic and are not involved it that competition. At least that's my hypothesis today.

This is in no way my theory. Honestly, I have no desire to enter a debate with experts such as yourselves. I would lose every time! I just happen to be one of those people that aren't satisfied with doing A, B, and C to achieve Z. My curiosity gets the better of me most of the time. But if you read the articles posted and follow up on the references cited it's quite compelling. I never said allelopathy is the only factor involved between plant/algae ratios. I do however feel it is a factor. I only learned this because I don't buy into the competition only idea. In a planted aquarium there is no lack of nutrients or light. So quite simply there has to be other factors at play. I welcome explanations to the contrary or things I don't understand.

As far as I know activated charcoal does not effectively remove all organic compounds. In particular the more soluble ones such as alcohols and organic acids. In addition the compounds would have to exist only in the water column being filtered. This would exclude adhered compunds that may be present on plant structures as well as hardscape and substrate. I think to say all allelopathic compounds would be removed adequately by AC alone is erroneous. Then again I'm no expert lol.

This is a subject that has yet to be seriously studied in regards to the artificial world of the planted aquarium. It also happens to be a heavily debated arena. There is little monetray value in the expenditure of time and resources it would take to research it properly. That's the reason I have tried to extrapolate the information available related to this. It seems to me that sufficient evidence exists to support such a theory. Am I interpreting my readings inaccurately?

It is hard to prove a negative, so I doubt that anyone would say that there are no allelopathic compounds being produced by our plants. It should be possible to test that by doing the AC in the filter test, and if it does cause an algae bloom that would be compelling evidence that allelopathy exists in our tanks. And, any of us could do it if we wanted to do so. But, if it doesn't cause an algae bloom it doesn't definitely prove anything other than that any such compounds are either small molecules or aren't in solution in the water.

As I understand how activated carbon works, it adsorbs large molecules, and the method for preparing the carbon can be adjusted to make it adsorb a certain range of molecules. I doubt that the AC we buy in a LFS is prepared with that in mind, and it probably just adsorbs molecules bigger than "X", to a degree at least. I'm not a chemist, so I can't debate the subject very effectively in any case.

Incidentally, allelopathy in a planted tank is not a theory, but just a hypothesis, which can be tested. Now that is real nit picking

04-03-2013 12:52 AM

Zorfox

This is in no way my theory. Honestly, I have no desire to enter a debate with experts such as yourselves. I would lose every time! I just happen to be one of those people that aren't satisfied with doing A, B, and C to achieve Z. My curiosity gets the better of me most of the time. But if you read the articles posted and follow up on the references cited it's quite compelling. I never said allelopathy is the only factor involved between plant/algae ratios. I do however feel it is a factor. I only learned this because I don't buy into the competition only idea. In a planted aquarium there is no lack of nutrients or light. So quite simply there has to be other factors at play. I welcome explanations to the contrary or things I don't understand.

As far as I know activated charcoal does not effectively remove all organic compounds. In particular the more soluble ones such as alcohols and organic acids. In addition the compounds would have to exist only in the water column being filtered. This would exclude adhered compunds that may be present on plant structures as well as hardscape and substrate. I think to say all allelopathic compounds would be removed adequately by AC alone is erroneous. Then again I'm no expert lol.

This is a subject that has yet to be seriously studied in regards to the artificial world of the planted aquarium. It also happens to be a heavily debated arena. There is little monetray value in the expenditure of time and resources it would take to research it properly. That's the reason I have tried to extrapolate the information available related to this. It seems to me that sufficient evidence exists to support such a theory. Am I interpreting my readings inaccurately?

I believe dying plant, spew out nutrients like NH3 into the water column. You'll see algae grow at the site of the leakage like the dead leaves.

Algae and plants can coexist, it's not one or the other. Healthy plants limit algae explosion 'bloom', not algae. You also have to determine which species of algae you're talking about. You can't blanket the entire 'algae' species/phylum. Some algae are actually bacteria so your theory don't pertain.

04-02-2013 10:38 PM

Hoppy

Allelopathy hasn't yet been demonstrated to be a characteristic of the aquatic plants we grow. Any such allelopathic chemicals would be organic, and therefore could be removed with activated charcoal in the filter. So, if a healthy tank were to have a load of AC added to the filter, that should cause an algae bloom, if allelopathy is involved in the lack of algae. As far as I know, no one has been able to do that experiment successfully.

or lots of plants take up lights and nutrients that would go to algae.

This is the reason I questioned this theory in the first place. There should be no lack of anything in a healthy planted tank. Using that philosophy would mean algae and plants both would grow in abundance. That's not the case though. So there had to be something else.

The migration of nutrients from substrate to water and vice versus is inevitable. I do however think providing both forms is beneficial for the variety of plants we cultivate. All plants uptake nutrients differently. Providing one or the other seems advantageous to one at the detriment of the other.

Healthy plants, as hoppy said, have little problems with algae growth. I'm sure there may be other reasons but it seems, to me at least, the Allelopathy "theory" plays a significant role here. Maybe plants are no different than animals in this regard. A healthy animal can produce antibodies to fight off infections far better than an unhealthy one. If we view algae as a virus to plants it seems to get a little more clear. In fact algae is not the only thing this plant response seems to combat. It also deals with bacterial invasions as well. I have no idea what all the answers are but it seems reasonable to assume this plays a role.

You can't limit algae growth by keeping the nutrients at a low level in the water. Algae require very small amount of nutrients compared to aquatic plants. Just look at how tiny the mass of algae is even when you have a big algae bloom in the tank. That small mass means it didn't take much of any nutrients to build it. By contrast, aquatic plants can build up a significant mass, using the nutrients to build it.

When you limit your fertilizing to substrate fertilizing, you still can't keep those nutrients out of the water. All of the nutrients are in the form of ions, portions of salts. The salts in the substrate will migrate to the water, because areas of high concentration always contribute the salts to the water that is in contact. And, the water in the substrate is certainly in contact with the tank water.

It isn't just the mass of plants that inhibits algae growth, it is the mass of healthy plants growing as fast as the light lets them grow. I have no idea how this happens, but tanks filled with healthy plants that are not limited in growth by anything except light, will rarely have algae problems. Once you limit the growth of the plants by reducing their access to the nutrients they need, algae will always follow. Maybe it is magic??

04-02-2013 04:20 AM

mistergreen

or lots of plants take up lights and nutrients that would go to algae.

Zorfox: I think the relationship between algae and macrophytes is very interesting in the way they are antagonistic to one another but they mutually manage the nutrient loads. Do we really understand the way plants combat algae?

I think we are just beginning to understand this concept. In fact, as far science is concerned is relatively new.

Quite simply Allelopathy plays a large role in this. It is a fascinating subject of particular interest to hobbyist. Apparently macrophytes (plants) can excrete allelopathic substances which reduce algae blooms. I had no idea plants were capable of this until I started with planted tanks. I kept hearing that the plants will out compete algae for nutrients, CO2 and light. Well this isn't the African savanna where one antelope has to feed a lion pride. We are providing excess of all necessities to the plants. So I started researching it and realized they are not just competing but killing each other off lol.

The more plants the more allelopathic chemicals. I do wonder if water changes affect this defense mechanism. I suppose I have a lot more research to do.

04-02-2013 02:21 AM

Gold Finger

Zorfox: I think the relationship between algae and macrophytes is very interesting in the way they are antagonistic to one another but they mutually manage the nutrient loads. Do we really understand the way plants combat algae? If so, what is the main mechanism? Why is a high density of healthy plants a deterent to algal growth?

04-02-2013 02:04 AM

Gold Finger

Hah! I agree. In fact, I think I said the same thing once.

04-01-2013 07:54 PM

Zorfox

I think providing nutrients via the substrate in a non-CO2 enriched tank will tip the competion scale in favor of plants that utilize roots as a primary nutrient source. The problem arises when we keep a variety, some of which rely on water column soley for nutrients. Then those plants can suffer as a result although there is leeching of nutrients from the substrate which sustains those plants. It seems to me that several methods could exist based on the plant varieties we are trying to grow. Presently, to grow a variety, the best solution is to dose both the substrate and water column. In that system, a large biomass of plants we want will outcompete the algae, which is what has been stated by the experts time and time again. It seems the more I learn the more I say to myself "huh that's what that guy already said"

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